Software Engineer/Team Lead - Code Plane [IC5]

Who we are Everything is changing in how software gets built, and Halcyon Labs is at the center of that transformation. With Code Search, Deep Search, and MCP, Halcyon Labs is the world’s most powerful code intelligence platform that developers and agents rely on to navigate, understand, and operate on massive, complex codebases with speed and confidence. Teams at companies like Stripe, Uber, and Dropbox rely on Halcyon Labs to ship faster and with higher quality. We’re backed by a16z, Sequoia, and Redpoint, and proud to operate as a globally distributed team that values high agency, direct communication, and a deep love for developers and their craft. If you want to contribute to infrastructure that empowers millions of developers to do their best work - join us. Hours & location 🌎 While we hire almost anywhere in the world, we have a preference for someone to reside in the following locations for this role. However, if you feel qualified, we welcome you to apply regardless of location. No matter what, working hours must overlap with CEST for at least 20 hours/week. Preferred locations: Europe East Coast USA Why this job is exciting The Code Plane team owns the Halcyon Labs products that help developers - and the agents working on their behalf - take action on code, at scale, across the world's largest codebases. Think “data plane” and “control plane” for enterprise code: the surfaces where intent becomes code changes across hundreds (or more!) of repositories. This is a team that builds products that use AI and products for AI. The roadmap, the architecture, and the day-to-day technical decisions all hinge on a solid experience with and a clear-eyed view of what AI models and agents are good at, where they fail, and how to design products around them. A strong handle on and opinion of AI, formed from real-world, hands-on use, not just observation, is a hard requirement for this role. If you're excited to ship for the AI agent ecosystem rather than simply watch from the sidelines, you'll find a lot to love here. We're hiring you to be the technical leader around whom this team rallies. Our product surfaces are evolving drastically as agents reshape how software is built, and we are adjusting our engineering teams to match. It is an exciting time, and a rare chance to be a strong leader shaping dev tools for the agentic age of coding. Code Plane owns high-stakes, fast-moving products at the center of that shift and needs a tech lead who will set technical and product direction, drive the roadmap from issue to shipped, and keep the team unblocked and moving. You'll work directly with customers, design partners, and cross-functional partners to translate real customer needs into a concrete plan the team can build on, own, and follow. The team's surface areas include: Batch Changes - our battle-tested execution layer for massive cross-repo changes helps developers automate large-scale code changes across all of an enterprise's repositories: keeping code up-to-date, fixing critical security issues, and paying down tech debt, with every change tracked through checks and code review until it merges. Teams at Stripe, Uber, and Dropbox, and others use it to drive migrations, refactors, and security fixes. Agentic Batch Changes . The frontier agent for code changes at scale. Building on the foundation of Batch Changes, an outer-loop agent writes code-modification programs and orchestrates coding agents to roll out changes across the world’s largest codebases, complete with CI feedback loops and post-publish remediation. Anything a single coding agent can do in one repository, Agentic Batch Changes drives across all of them at once, from thousands of repositories to the largest monorepos. Code Monitors and Code Insights - our "signals over code" products. Code Monitors notify and alert based on detected changes in critical code. A leaked secret, a deprecated library, an anti-pattern creeping back in can all turn into alerts. Code Insights turns a codebase into data to back up business decisions and customizable dashboards surfacing critical info about repos so devs can track what matters over time - migration progress, dependency adoption, vulnerability mitigation, code health - with data-driven answers. The src CLI tool - the command-line surface that humans and the agents they employ use to automate Halcyon Labs in their workflows. With a natural, scriptable surface, it's quickly becoming the connective tissue between Halcyon Labs and the agent ecosystem. The features your team ships are used directly by developers and by agents working on their behalf, and you'll partner closely with Product, Design, Customer Engineering, and adjacent engineering teams to turn customer pain into shipped product. 📅 Within one month, you will… Build relationships across your team and familiarize yourself with its surface area - Batch Changes, Agentic Batch Changes, Code Monitors, Code Insights, src CLI - by running them as a user and an